Flow, suspension and mixing dynamics in DASGIP bioreactors, Part 2

Abstract

This work aims to characterize the mixing and suspension dynamics occurring within two commercially available DASGIP bioreactor configurations, equipped with a twoblade paddle impeller with large impeller to tank diameter ratio, D/T = 0.97. Both continuous and intermittent agitation modes were employed to determine the impact that agitation strategy has upon mass transfer and microcarrier settling/suspension. This paper builds upon the flow dynamics data presented in Part 1 for a flat bottom DASGIP bioreactor and shows how intermittent agitation can break-up regions of slow mixing observed during continuous agitation, therefore substantially increasing the mixing efficiency of the system. Similarly, it was found that microcarrier characteristics might significantly affect the level of suspension when the impeller is in dwell status when intermittent agitation modes are used.

Functional composite microbeads for cell-based meat culture: effect of animal gelatin coating on cell proliferation and differentiation

“…Commercial microcarriers such as Cytodex and SoloHill [35,41] were fabricated using synthetic and inedible materials. Our microcarriers made of food-grade biopolymers have a similar density of 1.04 g cm −3 with Cytodex, which enables the beads to be suspended in the bioreactor in a large-scale cell culture.…”

The Colourimetric Method for Mixing Time Measurement in Single-Use and Multi-Use Bioreactors—Methodology Overview and Practical Recommendations

“…The biggest number of previously published papers, which included the colourimetric method for determination of mixing time, regarded stirred tank reactors and bioreactors, including, in some cases, single-use bioreactors [34][35][36]. The investigations included baffled and unbaffled classical tanks agitated with various equipment: Rushton turbines [3,10,[15][16][17]19,24,25,27,28,[31][32][33] and their variants (Scaba SRGT [15]), pitchedblade impellers [3,10,17,24,25,33], disk turbines [19], elephant ear [27,36] and marine blade impellers [27,34,35], hydrofoil [14], Maxblend™ [10,22,23], helical ribbon [13,18,29], a trapezoidal paddle [30], axial flow impellers [24] and planetary [18,21] and coaxial mixers [20]. Some papers contained results from experiments involving orbitally shaken devices, i.e., shake flasks [6], orbitally-shaken single-use bioreactors [37,38,…”

“…Typically, the maximum volume of the vessel analysed using the colourimetric method was no larger than 1000 L. The volume of analysed vessels ranged from the millilitre scale [6,27,30,33,38,44], including vessels from parallel bioreactor systems [35], through bench-scale and laboratory-scale devices [16][17][18][20][21][22]24,[27][28][29]31,32,34,36,37], up to pilotscale systems in the hundred-litre range [14,15,19,22,24,25]. However, one has to note the examples of large-scale reactors, such as the 1500 L orbitally shaken single-use plastic filmbased bag-like container analysed by Tissot et al [37] or the 15 m 3 stirred tank investigated by Rosseburg et al [3].…”

“…Therefore, the camera can usually be mounted stationarily in front of the tank with a view of a plane parallel to its vertical axis [2,28,29,32] (Figure 3). In their papers regarding the characterisation of small-scale cylindrical vessels, some authors mention placing the device inside a separate rectangular vessel filled with liquid of a similar composition and refractive index to the one inside the tank [10,20,22,[29][30][31]48,53]. This approach is used to minimise the distortions from the curved tank walls.…”

“…The choice of filming equipment depends primarily on its availability, cost, the desired size in relation to the experimental setup and existing inventory and expertise inside a research facility. The literature contains reports of the use of industrial solutions [6,30,33,36,40,44] or consumer-grade devices such as digital SLRs [27,28,31,57], mirrorless [45] or compact digital cameras [26,29,32,37,38] or webcams [18]. Other consumer equipment could be suitable for a colourimetric method setup, including action cameras or widely available smartphone cameras.…”